NMR.-Study of nitrogen inversion and conformation of 1,5-dihydro-isoalloxazines ("reduced flavin"). Studies in the flavin series, XIX.
NMR.-Study of nitrogen inversion and conformation of 1,5-dihydro-isoalloxazines ("reduced flavin"). Studies in the flavin series, XIX.
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NMR.-1,5-二氢异咯嗪（“还原黄素”）的氮转化和构象研究。
DOI：
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发表时间：
1973
影响因子：
1.8
通讯作者：
Peter Hemmerich
中科院分区：
文献类型：
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作者：
Ludwig Tauscher;Sandro Ghisla;Peter Hemmerich
用核磁共振方法测定了几种还原黄素的N(5)中心的锥形反转。在丙酮溶液中的反转势垒为10kcal/∼，且与N(5)取代基的大小无关。当N(5)取代基只能处于轴向位置时，∼的反转势垒增大，而N(5)酰基取代基的∼翻转势垒增加3.5kcal/m o l。在水溶液中，反转势垒增加了3kcal/∼。讨论了还原黄素的立体化学及其在依赖黄素的生物脱氢中的潜在关联。
The pyramidal inversion of the N(5)-centre of several reduced flavins was measured by NMR. The inversion barrier was found to be ∼10 kcal/mol in acetone solutions and to be independent of the size of the N(5) substituent. An increase of the inversion barrier of ∼5 kcal/mol was observed in the case where the N(5) substituent could only be in axial position, and an increase of ∼3.5 kcal/mol was observed for an acyl-like N(5) substituent. In aqueous solution the inversion barrier increases by ∼3 kcal/mol. The stereochemistry of reduced flavin and its potential relevance in flavin-dependent biological dehydrogenations is discussed.